1. Energy Efficiency and Renewable Energy Chapter 16

2. ICELAND

3. Iceland  No known reserves of oil, natural gas or coal  200 miles from the arctic circle  Warmed by the Gulf Stream  Sits on top of a divergent boundary between the European and North American plate and a hot spot in the Earth’s mantle What kind of energy resources should they use?

4. Iceland’s Vision of a Renewable-Energy Economy (1)  Supplies 75% of its primary energy and almost all of its electrical energy using Geothermal energy Hydroelectric power Wind power Imports oil to run transportation, factories, make products  Bragi Arnason: “Dr. Hydrogen” Vision to use in country resources to produce hydrogen fuel to run everything by 2060

5. Core Case Study: Iceland’s Vision of a Renewable-Energy Economy (2)  2003: World’s first commercial hydrogen filling station  2003–2007: three prototype fuel-cell buses  2008: 10 Toyota Prius test vehicles Hydrogen-fueled  Whale-watching boat: partially powered by a hydrogen fuel cell

6. The Krafla Geothermal Power Station in Northern Iceland

7. Visions  Do you think Iceland’s energy vision should be ours? Explain  What do you think would be the easiest change For the US that would move us towards a more self-sustaining, environmentally positive existence

8. 16-1 Why Is Energy Efficiency an Important Energy Resource?  Concept 16-1 We could save as much as 43% of all the energy we use by improving energy efficiency.

9. Energy Waste in the last 24 hours What have you witnessed? Done?

10. Where do you waste the most energy?  Using non-recyclable material, (why?)  Living in a prepackaged, throw-away society (why?)  Having a house not properly insulated (why?)  Driving alone in a large car/SUV (why?)  Solutions?

11. We Waste Huge Amounts of Energy (1)  Energy conservation  Energy efficiency  Advantages of reducing energy waste: Quick and clean Usually the cheapest to provide more energy Reduce pollution and degradation Slow global warming Increase economic and national security

12. Fig. 16-2, p. 401 Energy InputsSystemOutputs 9% 7% 41%85% U.S. economy 43% 8% 4% 3% Nonrenewable fossil fuels Useful energy Nonrenewable nuclearPetrochemicals Unavoidable energy waste BiomassUnnecessary energy waste Hydropower, geothermal, wind, solar

13. Waste Unavoidable Waste? –Examples –How is it related to the law of Entropy? Avoidable Waste? –Examples –How do constructing individual homes in the suburbs increase the avoidable waste of the system?

14. We Waste Huge Amounts of Energy (2)  Four widely used devices that waste energy Incandescent light bulb (90%) Motor vehicle with an internal combustion engine (94%) Nuclear power plant (why?) (83%) Coal-fired power plant (why?) (66%)  Possible alternatives for the “outdated four”

15. List as many advantages we gain by reducing avoidable waste

16. Fig. 16-3, p. 401 Advantages Reducing Energy Waste Prolongs fossil fuel supplies Reduces oil imports and improves energy security Very high net energy yield Low cost Reduces pollution and environmental degradation Buys time to phase in renewable energy Creates local jobs

17. Net Energy Efficiency—Honest Energy Accounting  Net energy efficiency the only energy that counts

18. Fig. 16-4, p. 402 Electricity from Nuclear Power Plant Uranium processing and transportation (57%) Uranium mining (95%) Power plant (31%) Transmission of electricity (85%) Resistance heating (100%) Uranium 100% 95%54% 17% 14% Passive Solar Window transmission (90%) Sunlight 100% 90% Waste heat 14%

19. What can the school do to reduce energy waste? Are all suggestions practical?

20. 16-2 How Can We Cut Energy Waste?  Concept 16-2 We have a variety of technologies for sharply increasing the energy efficiency of industrial operations, motor vehicles, and buildings.

21. What kind of car do you drive, if you drive? What kind of car do you want to drive in the future?

22. We Can Save Energy and Money in Industry (1)  30% or world’s and 38% of US energy consumption  Cogeneration or combined heat and power (CHP) (capturing waste heat  steam)

23. Recycling materials  Uses 75% less energy to produce steel out of recycled materials than dig more out of the earth

24. Better Engines  Replace energy-wasting electric motors  Consume1/4 of all electricity created in US  Most run at full speed, more power output than needed

25. Switch the Types of lights  LED (light emitting diodes)  1/7 th as much energy  100 times as long  Compact Fluorescent bulbs  1/4 th as much energy  10 times as long

26. We Can Save Energy and Money in Industry (2)  Electrical grid system: outdated and wasteful: It takes energy moving electricity through wires  Utility companies promote use of energy, not energy efficiency -Wireless distribution of energy -Smaller distance between source and end use Dow Chemical has cut energy consumption by 25% in 8 years: What does that do for profits?

27. Fig. 16-5a, p. 404 25 Cars 20 Cars, trucks, and SUVs Trucks and SUVs 15 Average fuel economy (miles per gallon) 10 19751980 1985 1990199520002005 Year

28. Fig. 16-5b, p. 404

29. We Can Save Energy and Money in Transportation  Corporate average fuel standards (CAFE) standards Fuel economy standards lower in the U.S. than many other countries  Fuel-efficient (35 mpg) cars are on the market  1% of cars, trucks are fuel-efficient

30. What would you pay for gas  What costs have to be included to determine the “true” price we pay for gasoline 1)____________________ (gov) 2)____________________ (dam) 3)____________________ (mil) 4)____________________ (med) How much do you think the average person truly pays for a gallon of gas today?

31.  Should there be tax breaks for buying fuel- efficient cars?  Should there be tax breaks for buy fuel inefficient cars?  What do you think is a feebate?

32. More Energy-Efficient Vehicles Are on the Way  Superefficient and ultra light cars  Gasoline-electric hybrid car  Plug-in hybrid electric vehicle  Energy-efficient diesel car  Electric vehicle with a fuel cell

33. Ultra light, Ultra strong car  How does ultra light car gain advantages?

34. Gas-hybrid car  Gas is main source of energy  Motor also acts as generator, converting motion of car back into energy  New energy stored in battery

35. How a gasoline-hybrid works  The electric motor applies resistance to the drive-train causing the wheels to slow down.  In return, the energy from the wheels turns the motor,  which functions as a generator, converting energy normally wasted during coasting and braking into electricity,  which is stored in a battery until needed by the electric motor.

36. Plug in electric hybrid  electric car is powered by an electric motor instead of a gasoline engine  Still use motor as generator to recycle energy

37. Fig. 16-6, p. 405 Stepped Art Conventional hybridFuel tank Battery Internal combustion engine TransmissionElectric motor Plug-in hybrid Fuel tank Battery Internal combustion engine Transmission Electric motor

38. Compare Electric to gas cars  Any other comparisons?

39. Energy efficient diesel cars  This fuel can be made out of coal, plant material or cooking oil  45% of new passenger sales in Europe  Modern diesel engines are Quieter 30% more fuel efficient 20& less CO 2 emissions Biodiesel (more detail) Hybrid-diesel

40. Fuel Cells  What do you think they are?  How do you think they produce energy?  What waste products result from fuel cell use?

41. Fuel Cells  At least twice as efficient as an internal combustion engine  Has no moving parts, requires little maintenance  Uses hydrogen gas as fuel  Does not produce CO2 or other toxins as pollutants  In show rooms by 2012  Very expensive  Discuss in more detail later in chapter

42. Science Focus: The Search for Better Batteries  Current obstacles Storage capacity Overheating Flammability  In the future Lithium-ion battery Ultracapacitor Viral battery Using nanotechnology

43. Lithium Ion batteries  Found in laptops and cell phones  Less weight, space as Ni-Cd batteries  Occasional tendency to overheat, burst into flames

44. Other battery types  Using nanotechnology to make a nonflammable battery Nanophosphate material Not heat up or release oxygen  Genetically engineered virus MIT Coat itself with conductive materials (nanowire) Grow themselves Use water as a solvent Yield none of the toxic residue in disposal

45. Questions: 1) What car do you have access to drive? 2) can it be considered fuel efficient? 3) If so, what features make it fuel efficient? If not, what features do not make it fuel efficient 4) What are the differences between the different types of hybrid cars? 5) What makes the diesel cars in the future more efficient? 6) What is the difference between a fuel cell and a battery? 7) What kind of car do you want in the future? What features will it have to promote a healthy environment?

46. We Can Design Buildings That Save Energy and Money (1)  Green architecture: energy-efficient, money savings designs, uses recycled building materials, rainwater collection, nontoxic paint, glues…  Living or green roofs: capture energy, rainwater, green space  Straw bale houses  U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED)

47. We Can Design Buildings That Save Energy and Money (2)  Two buildings that were designed with energy in mind Georgia Power Company in Atlanta, GA (U.S.) Ministry of Science and Technology Building in Beijing, China

48. A Green or Living Roof in Chicago, IL (U.S.)

49. Straw bale house  Renewable  Insulation  Moisture, Movement

50. We Can Save Energy and Money in Existing Buildings (1)  Insulate and plug leaks  Use energy-efficient windows  Stop other heating and cooling losses  Heat houses more efficiently

51. We Can Save Energy and Money in Existing Buildings (2)  Heat water more efficiently  Use energy-efficient appliances  Use energy-efficient lighting

52. A Thermogram Showing Heat Loss Around Houses and Stores

53. Ways to save money where you live

54. Fig. 16-9, p. 409 Attic Hang reflective foil near roof to reflect heat. Use house fan. Be sure attic insulation is at least 30 centimeters (12 inches). Bathroom Install water-saving toilets, faucets, and shower heads. Repair water leaks promptly. Kitchen Use microwave rather than stove or oven as much as possible. Run only full loads in dishwasher and use low- or no-heat drying. Clean refrigerator coils regularly. Basement or utility room Use front-loading clothes washer. If possible run only full loads with warm or cold water. Hang clothes on racks for drying. Run only full loads in clothes dryer and use lower heat setting. Set water heater at 140° if dishwasher is used and 120° or lower if no dishwasher is used. Use water heater thermal blanket. Insulate exposed hot water pipes. Regularly clean or replace furnace filters. Outside Plant deciduous trees to block summer sun and let in winter sunlight. Other rooms Use compact fluorescent lightbulbs or LEDs and avoid using incandescent bulbs wherever possible. Turn off lights, computers, TV, and other electronic devices when they are not in use. Use high efficiency windows; use insulating window covers and close them at night and on sunny, hot days. Set thermostat as low as you can in winter and as high as you can in summer. Weather-strip and caulk doors, windows, light fixtures, and wall sockets. Keep heating and cooling vents free of obstructions. Keep fireplace damper closed when not in use. Use fans instead of, or along with, air conditioning.

55. Homework What is used around your home?

56. Why Are We Still Wasting So Much Energy?  Energy remains artificially cheap  Few large and long-lasting government incentives (Door, window, insulation incentive just stopped January)  What about the rebound effect? Use more energy because of savings

57. We Can Use Renewable Energy in Place of Nonrenewable Energy Sources  Renewable energy Solar energy: direct or indirect Geothermal energy Moving water or wind  Benefits of shifting toward a variety of locally available renewable energy resources Decentralization of supply less vulnerable to natural disasters, supply cutoffs Creation of high quality jobs

58. Cost of renewable energy  Forms of renewable energy would be cheaper if we eliminate Inequitable subsidies: Oil, Nuclear vs Solar Inaccurate prices: environmental and health costs

59. What do you know?  BY Friday:  Definition, equipment  How does it produce heat or energy  Limitations of use  Advantages  Disadvantages  Sources:  A) Passive solar heating  B) Solar cells  C) Hydroelectric sources  D) Wind  E) Geothermal

60. 16-3 What Are the Advantages and Disadvantages of Solar Energy?  Concept 16-3 Passive and active solar heating systems can heat water and buildings effectively, and the costs of using direct sunlight to produce high-temperature heat and electricity are coming down.

61. We Can Heat Buildings and Water with Solar Energy  Passive solar heating system: absorbs and stores heat from sun directly  Active solar heating system: absorbs heat into water/antifreeze and then pumps liquid to other areas  Energy is moderate with planning

62. Passive Solar heating South Facing Window types Window size Summer/winter Windows for air

63. We Can Cool Buildings Naturally  Technologies available Superinsulation and high-efficiency windows Overhangs or awnings on windows Light-colored roof Reflective insulating foil in an attic Geothermal pumps Plastic earth tubes underground

64. Rooftop Solar Hot Water on Apartment Buildings in Kunming, China

65. Solutions: Passive and Active Solar Heating for a Home

66. Fig. 16-10a, p. 411 Vent allows hot air to escape in summer Summer sun Heavy insulation Winter sun Superwindow Stone floor and wall for heat storage PASSIVE

67. Fig. 16-10b, p. 411 Solar collectorHeat to house (radiators or forced air duct) Pump Heavy insulation Super- window Hot water tank Heat exchanger ACTIVE

68. Fig. 16-11, p. 412 TRADE-OFFS Passive or Active Solar Heating AdvantagesDisadvantages Energy is free Need access to sun 60% of time Net energy is moderate (active) to high (passive) Sun can be blocked by trees and other structures Quick installation Environmental costs not included in market price No CO 2 emissions Very low air and water pollution Need heat storage system Very low land disturbance (built into roof or windows) Active system needs maintenance and repair High cost (active) Active collectors unattractive Moderate cost (passive)

69. Solutions: Woman in India Uses a Solar Cooker

70. We Can Use Sunlight to Produce High- Temperature Heat and Electricity  Solar thermal systems Central receiver system Other collecting systems  Unfeasible for widespread use High cost Low new energy yields Limited suitable sites Sunny, desert sites

71. Solar oven on steroids

72. Commercial Solar Power Tower Plant Near Seville in Southern Spain

73. Trade-Offs: Solar Energy for High- Temperature Heat and Electricity

74. Case Study: The Rocky Mountain Institute—Solar Powered Office and Home  Location: Snowmass, CO (U.S.)  No conventional heating system 90% of electricity, 99% of hot water from sun  Heating bills: <$50/year (costs)  How is this possible? Combination of energy efficiency, passive and active solar heating and solar cells

75. Sustainable Energy: Rocky Mountain Institute in Colorado, U.S.

76. Solar Panels

77. Fig. 16-17a, p. 415

78. We Can Use Solar Cells to Produce Electricity (1)  Photovoltaic (PV) cells (solar cells) Convert solar energy to electric energy  Solar-cell power plants Near Tucson, AZ (U.S.) 2007: Portugal  Solar-cell systems being built or planned in Leipzig, Germany South Korea South California (U.S.) China

79. Solar-Cell Power Plant in Arizona, U.S., Is the Largest Solar-Cell Power Plant

80. How panel works  Photons of sunlight enter panel (UV, Vis, Infrared)  Absorbed by silicon material which in turn emitted energized electrons  Metal layer gathers energy from electrons  electric current is created

81. We Can Use Solar Cells to Produce Electricity (3)  Uses: solar panels work everywhere, do not have to be connected to grid  Key problem High cost of producing electricity  Will the cost drop with Mass production New designs Nanotechnology (multiple layers, size of panels)

82. Fig. 16-20, p. 417 TRADE-OFFS Solar Cells Advantages Disadvantages Fairly high net energy yield Need access to sun Work on cloudy days Low efficiency Easily expanded or moved Need electricity storage system or backup Quick installation Environmental costs not included in market price No CO 2 emissions Low environmental impact High costs (but should be competitive in 5–15 years) Low land use (if on roof or built into walls or windows) High land use (solar- cell power plants) could disrupt desert areas Last 20–40 years Reduces dependence on fossil fuels DC current must be converted to AC

83. Solutions: Solar Cells Used to Provide Electricity for a Remote Village in Niger

84. Total Costs of Electricity from Different Sources in 2004

85. The Solar Power Industry Is Expanding Rapidly  Solar cells: 0.2% of the world’s electricity  2040: could solar cells produce 16%?  Nanosolar: California (U.S.)  Germany: huge investment in solar cell technology  General Electric: entered the solar cell market

86. Exit Questions 16.3  What is the difference between active and passive solar heating  What is a photovoltaic cell?  Name 3 advantages and disadvantages of generating electricity by photovoltaic cells?

87. 16-4 Advantages and Disadvantages of Producing Electricity from the Water Cycle  Concept 16-4 Water flowing over dams, tidal flows, and ocean waves can be used to generate electricity, but environmental concerns and limited availability of suitable sites may limit the use of these energy resources.

88. We Can Produce Electricity from Falling and Flowing Water  Hydropower World’s leading renewable energy source used to produce electricity Hydroelectric power: Iceland  Advantages  Disadvantages  Micro-hydropower generators

89. Trade-Offs: Large-Scale Hydropower, Advantages and Disadvantages

90. Fig. 16-21, p. 418 TRADE-OFFS Large-Scale Hydropower Advantages Disadvantages Moderate to high net energy High construction costs High efficiency (80%) High environmental impact from flooding land to form a reservoir Large untapped potential Environmental costs not included in market price Low-cost electricity Long life span High CO 2 emissions from rapid biomass decay in shallow tropical reservoirs No CO 2 emissions during operation in temperate areas Danger of collapse Can provide flood control below dam Uproots people Decreases fish harvest below dam Provides irrigation water Decreases flow of natural fertilizer (silt) to land below dam Reservoir useful for fishing and recreation

91. 16-4 Advantages and Disadvantages of Producing Electricity from the Water Cycle Concept 16-4 Water flowing over dams, tidal flows, and ocean waves can be used to generate electricity, but environmental concerns and limited availability of suitable sites may limit the use of these energy resources.

92. We Can Produce Electricity from Falling and Flowing Water Hydropower –World’s leading renewable energy source used to produce electricity –Hydroelectric power: Iceland, Quebec-Canada Advantages Disadvantages Micro-hydropower generators: suitcase sized turbines, portable generators

93. Micro hydro power

94. Fig. 16-21, p. 418 TRADE-OFFS Large-Scale Hydropower Advantages Disadvantages Moderate to high net energy High construction costs High efficiency (80%) High environmental impact from flooding land to form a reservoir Large untapped potential Environmental costs not included in market price Low-cost electricity Long life span High CO 2 emissions from rapid biomass decay in shallow tropical reservoirs No CO 2 emissions during operation in temperate areas Danger of collapse Can provide flood control below dam Uproots people Decreases fish harvest below dam Provides irrigation water Decreases flow of natural fertilizer (silt) to land below dam Reservoir useful for fishing and recreation

95. Tides and Waves Can Be Used to Produce Electricity (1) Produce electricity from flowing water –Ocean tides and waves –Tidal flow in rivers So far, power systems are limited –Norway –New York City

96. Tides and Waves Can Be Used to Produce Electricity (2) Disadvantages –Few suitable sites –High costs –Equipment damaged by storms and corrosion –Ecosystem interaction

97. 16-5 Advantages and Disadvantages of Producing Electricity from Wind Concept 16-5 When environmental costs of energy resources are included in market prices, wind energy is the least expensive and least polluting way to produce electricity.

98. Using Wind to Produce Electricity Is an Important Step toward Sustainability (1) Wind: indirect form of solar energy –Captured by turbines –Converted into electrical energy Second fastest-growing source of energy –Jobs, idled factories What is the global potential for wind energy? –Europe leading the way Wind farms: on land and offshore

99. Fig. 16-22a, p. 420

100. Solutions: Wind Turbine and Wind Farms on Land and Offshore

101. Using Wind to Produce Electricity Is an Important Step toward Sustainability (2) “Saudi Arabia of wind power” –North Dakota –South Dakota –Kansas –Texas –Delaware? How much electricity is possible with wind farms in those states?

102. Fig. 16-22a, p. 420 Gearbo x Electrical generator Power cable Wind turbine

103. Fig. 16-22b, p. 420 Wind farm

104. Fig. 16-22c, p. 420 Wind farm (offshore)

105. Producing Electricity from Wind Energy Is a Rapidly Growing Global Industry Countries with the highest total installed wind power capacity –Germany –United States –Spain –India –Denmark Installation is increasing in several other countries

106. Wind Energy Is Booming but Still Faces Challenges Advantages of wind energy “ Put in my back yard” (PIMBY) Drawbacks –Windy areas may be sparsely populated Need to upgrade the electric grid –Winds die down; need back-up energy –Storage of wind energy –Kills migratory birds (perches, nests, speeds, locations) –“Not in my backyard” (NIMBY)

107. Birds and turbines 40,000 birds/bats a year Old designs Placed in migratory paths Windows= 1 billion birds Transmission lines =175 million Feral Cats = 100 million Global warming more dangerous

108. Fig. 16-23, p. 421 TRADE-OFFS Wind Power AdvantagesDisadvantages Moderate to high net energy yield Steady winds needed High efficiency Backup systems needed when winds are low Moderate capital cost Low electricity cost (and falling) Plastic components produced from oil Very low environmental impact Environmental costs not included in market price No CO 2 emissions High land use for wind farm Quick construction Easily expanded Visual pollution Can be located at sea Noise when located near populated areas Land below turbines can be used to grow crops or graze livestock Can kill birds and interfere with flights of migratory birds

109. According to energy analysts: Wind has more benefits and fewer serious drawbacks than any other energy resource, except energy efficiency

110. 16-6 Advantages and Disadvantages of Biomass as an Energy Source (1)  Concept 16-6A Solid biomass is a renewable resource, but burning it faster than it is replenished produces a net gain in atmospheric greenhouse gases, and creating biomass plantations can degrade soil biodiversity.

111. 16-6 Advantages and Disadvantages of Biomass as an Energy Source (2)  Concept 16-6B Liquid biofuels derived from biomass can be used in place of gasoline and diesel fuels, but creating biofuel plantations could degrade soil and biodiversity and increase food prices and greenhouse gas emissions.

112. We Can Convert Plants and Plant Wastes to Liquid Biofuels (1)  Liquid biofuels Biodiesel (oils extracted from soybean, palm) Ethanol (alcohol, fermentation of sugars)  Biggest producers of biofuel Brazil The United States The European Union China

113. We Can Convert Plants and Plant Wastes to Liquid Biofuels (2)  Major advantages over gasoline and diesel fuel produced from oil Biofuel crops can be grown almost anywhere No net increase in CO 2 emissions if managed properly (farm/processing concerns) Available now

114. We Can Convert Plants and Plant Wastes to Liquid Biofuels (3)  Studies warn of problems: Decrease biodiversity Increase soil degrading, erosion, and nutrient leaching What fuel is used to grow crops? Raise food prices

115. Case Study: Is Biodiesel the Answer?  Biodiesel production from vegetable oil from various sources Soybeans Sunflowers Oil palms Used vegetable oils from restaurants  95% produced by The European Union Rapeseeds and sunflowers

117. Jatropha shrub: promising new source for biodiesel Advantages: oil burned without refining grown in hot dry tropical areas unlikely to threaten rain forests, displace food crops does not need a lot of fertilizers Disadvantages: Invasive species Ecosystems damaged thru land development

118. Jatropha Plant, other possible sources

119. Algae farms

120. Palm Oils

121. Problems with palm oil

122. Trade-Offs: Biodiesel, Advantages and Disadvantages

123. Fig. 16-25, p. 424 TRADE-OFFS Biodiesel AdvantagesDisadvantages Reduced CO emissions Increased NO x emissions and more smog Reduced CO 2 emissions (78%) Higher cost than regular diesel High net energy yield for oil palm crops Environmental costs not included in market price Low net energy yield for soybean crops Moderate net energy yield for rapeseed crops May compete with growing food on cropland and raise food prices Reduced hydrocarbon emissions Loss and degradation of biodiversity from crop plantations Better gas mileage (40%) Potentially renewable Can make engines hard to start in cold weather

124. Solid Biomass Wood, Dung, Farm industry, timber industry and Urban wastes “Trash to steam” Its environmental impact relates to its source (waste -vs- plantation) Burning waste and chemical residues Plantations and competition with crops

125. Fig. 16-24, p. 422 TRADE-OFFS Solid Biomass AdvantagesDisadvantages Large potential supply in some areas Nonrenewable if harvested unsustainably Moderate to high environmental impact Moderate costs No net CO 2 increase if harvested, burned, and replanted sustainably Environmental costs not included in market price Increases CO 2 emissions if harvested and burned unsustainably Low photosynthetic efficiency Plantation can be located on semiarid land not needed for crops Soil erosion, water pollution, and loss of wildlife habitat Can make use of agricultural, timber, and urban wastes Often burned in inefficient and polluting open fires and stoves Plantations could compete with cropland Plantation can help restore degraded lands

126. Case Study: Is Ethanol the Answer? (1)  Ethanol converted to gasohol (15% ethanol)  Flexible fuel cars can run on pure ethanol (15% gasoline)

127. Brazil: “Saudi Arabia of sugarcane” Brazil: ethanol from sugarcane Saved $50 billion in oil import costs since the 1970s 45% of cars run on residue grown on 1% of arable land Bagasse (sugarcane residue) has a net energy yield favorable to gasoline  United States: ethanol from corn Generous subsidies Provides net energy yield about 1/4 th as much as bagasse Net increase in global warming gases Competes with food production

128. Case Study: Is Ethanol the Answer? (2)  Cellulosic ethanol: alternative to corn ethanol  Sources Switchgrass Crop residues Municipal wastes (sawdust)  Advantages: Higher net yield, less crop, land fertilizers  Disadvantages: large amounts of land, difficult to break down

129. Fig. 16-27, p. 426 TRADE-OFFS Ethanol Fuel AdvantagesDisadvantages High octaneLower driving range Low net energy yield (corn) Some reduction in CO 2 emissions (sugarcane bagasse) Higher CO 2 emissions (corn) Much higher cost High net energy yield (bagasse and switchgrass) Environmental costs not included in market price May compete with growing food and raise food prices Reduced CO emissions Higher NO x emissions and more smog Can be sold as E85 or pure ethanol Corrosive Can make engines hard to start in cold weather Potentially renewable

130. 16-7 What Are the Advantages and Disadvantages of Geothermal Energy?  Concept 16-7 Geothermal energy has great potential for supplying many areas with heat and electricity and generally has a low environmental impact, but locations where it can be exploited economically are limited.

131. Fig. 16-28, p. 427 Basement heat pump

132. Getting Energy from the Earth’s Internal Heat (1)  Geothermal energy: heat stored in Soil Underground rocks Fluids in the earth’s mantle  Geothermal heat pump system Energy efficient and reliable Environmentally clean Cost effective to heat or cool a space

133. Geothermal energy: How does it work for an individual home?  Underground is at a constant temp  Pump water or antifreeze into ground to gain or lose heat  Pump cold or hot material back into house and use blowers to move hot/cool air into home  Needs electricity to run pumps

134. Geothermal energy: How does it work on larger scale?  Hydrothermal reservoirs  Dry air, wet steam or hot water heated by magma

135. Advantages  Can be very efficient in producing heat/electricity  Low disturbance of land  Moderate emissions, low compared to gas/coal

136. Hydrothermal plants in Iceland

137. Getting Energy from the Earth’s Internal Heat (2)  Geothermal energy: problems High cost of tapping large-scale hydrothermal reservoirs Dry- or wet-steam geothermal reservoirs could be depleted Hot water has minerals dissolved into it Limited resources/places Can Delaware produce large scale geothermal plants

138. Fig. 16-29, p. 428 TRADE-OFFS AdvantagesDisadvantages Geothermal Energy Very high efficiencyScarcity of suitable sites Moderate net energy at accessible sites Can be depleted if used too rapidly Environmental costs not included in market price Lower CO 2 emissions than fossil fuels CO 2 emissions Low cost at favorable sites Moderate to high local air pollution Low land use and disturbance Noise and odor (H 2 S) Moderate environmental impact High cost except at the most concentrated and accessible sources

139. 16-8 The Advantages and Disadvantages of Hydrogen as an Energy Source  Concept 16-8 Hydrogen fuel holds great promise for powering cars and generating electricity, but to be environmentally beneficial, it would have to be produced without the use of fossil fuels.

140. Hydrogen Is a Promising Fuel but There Are Challenges (1)  Hydrogen as a fuel Eliminate most of the air pollution problems Reduce threats of global warming  Some challenges Chemically locked in water and organic compounds Fuel cells are the best way to use hydrogen CO 2 levels dependent on method of hydrogen production

141. Hydrogen Is a Promising Fuel but There Are Challenges (2)  Production and storage of H 2  Hydrogen-powered vehicles: prototypes available  Can we produce hydrogen on demand?  Larger fuel cells

142. A Fuel Cell Separates the Hydrogen Atoms’ Electrons from Their Protons

143. Fig. 16-30, p. 429 Anode Polymer Electrolyte Membrane Cathode Air (O 2 ) in Water (H 2 O) out Hydrogen gas (H 2 ) in Protons Electrons

144. Trade-Offs: Hydrogen, Advantages and Disadvantages

145. Fig. 16-31, p. 430 TRADE-OFFS Hydrogen Advantages Fuel cell Disadvantages Can be produced from plentiful water Not found as H 2 in nature Energy is needed to produce fuel Low environmental impact Negative net energy Renewable if produced from renewable energy resources CO 2 emissions if produced from carbon- containing compounds No CO 2 emissions if produced from water Environmental costs not included in market price Good substitute for oil Nonrenewable if generated by fossil fuels or nuclear power Competitive price if environmental and social costs are included in cost comparisons High costs (that may eventually come down) Easier to store than electricity Will take 25 to 50 years to phase in Short driving range for current fuel-cell cars Safer than gasoline and natural gas No fuel distribution system in place Nontoxic High efficiency (45– 65%) in fuel cells Excessive H 2 leaks may deplete ozone in the atmosphere

146. 16-9 How Can We Make a Transition to a More Sustainable Energy Future?  Concept 16-9 We can make a transition to a more sustainable future if we greatly improve energy efficiency, use a mix of renewable energy resources, and include environmental costs in the market prices of all energy resources.

147. Choosing Energy Paths (1)  How will energy policies be created?  Supply-side, hard-path approach  Demand-side, soft-path approach

148. Choosing Energy Paths (2)  General conclusions about possible energy paths Gradual shift to smaller, decentralized micropower systems Transition to a diverse mix of locally available renewable energy resources Improved energy efficiency How? Fossil fuels will still be used in large amounts Why?

149. Solutions: Decentralized Power System

150. Fig. 16-32, p. 431 Small solar-cell power plants Bioenergy power plants Wind farm Fuel cells Rooftop solar-cell arrays Solar-cell rooftop systems Transmission and distribution system Commercial Small wind turbine Residential IndustrialMicroturbines

151. Solutions: Making the Transition to a More Sustainable Energy Future

152. Fig. 16-33, p. 432 SOLUTIONS Making the Transition to a More Sustainable Energy Future Improve Energy Efficiency More Renewable Energy Increase fuel-efficiency standards for vehicles, buildings, and appliances Greatly increase use of renewable energy Provide large subsidies and tax credits for use of renewable energy Mandate government purchases of efficient vehicles and other devices Include environmental costs in prices for all energy resources Encourage government purchase of renewable energy devices Provide large tax credits or feebates for buying efficient cars, houses, and appliances Greatly increase renewable energy research and development Reduce Pollution and Health Risk Offer large tax credits for investments in energy efficiency Cut coal use 50% by 2020 Phase out coal subsidies Reward utilities for reducing demand for electricity Levy taxes on coal and oil use Greatly increase energy efficiency research and development Phase out nuclear power subsidies, tax breaks, and loan guarantees

153. Economics, Politics, Education, and Sustainable Energy Resources  Government strategies: Keep the prices of selected energy resources artificially low to encourage their use Keep energy prices artificially high for selected resources to discourage their use Consumer education

154. What Can you Do? Shifting to Sustainable Energy Use

155. Case Study: California’s Efforts to Improve Energy Efficiency  High electricity costs  Reduce energy waste  Use of energy-efficient devices  Strict building standards for energy efficiency